Oh yeah, one more bit of "obvious" info that may need to be spelled out. Don't give these companies your real phone number. They don't NEED the phone number to send you the mags, don't give it to them. I've got a "fake" that I give out at every opportunity.
If a company needs to send you something by mail (i.e. free mags, free samples), give them your address. They don't need your phone number on top of that. You're only asking for harrassment. I think you should protect your phone number much more securely than your address.